Manufacture of organoaluminum compounds



a r il United States PatentO MANUFACTURE OF ORGANOALUMINUM COMPOUNDS Alfred F. Meiners and Francis V. Morriss, Kansas City, Mo., assignors to Ethyl Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Aug. 28, 1959, Ser. No. 836,612 9 Claims. (Cl. 260-448) cally, the compounds of aluminum having one or more" hydrocarbon substituents, have, of recent years, become important for various purposes. These purposes include, for example, use as catalysts or catalyst components for the polymerization of olefinic materials, and as starting materials for the generation of certain organic chemicals such as alcohols or the like. Of particular interest has been the production of certain organo compounds of aluminum of this character, that is, comprising aluminum, carbon and hydrogen, wherein the aluminum has at least one, and usually three normal alkyl substituents of relatively long chain length. In particular, alkyl compounds wherein the alkyl group has from six to ten carbon atoms have been of particular interest. Such materials are ideal for the generation of relatively high molecular weight,

straight chain monohydroxy compounds or alcohols, these products being achieved by the oxidation and then hydrolysis of the aluminum alkyl compound, resulting in the formation of aluminum oxide and the corresponding alcohol. A pronounced disadvantage to this route to the higher alcohols, has been the difficulty in achieving alkyl aluminum compounds of a more or less homogeneous nature and with relatively long chain alkyl substituents. According to US. Patent 2,826,598, by Ziegler and Gellert, it is feasible to engender long chain aluminum alkyl compounds by a growth reaction between aluminum triethyl, for example, and ethylene. It appears that ethylene adds to the alkyl aluminum compound in multiples thereof and produces an extension of the alkyl group to a relatively long length. However, it is also found, that the respective length of these alkyl substituents is of random distribution, so that a high degree of specificity is not achieved. Accordingly, if such a tri-alkyl compound is reacted to produce alcohols as outlined above, the alcoholic product thus produced is lacking in the specific character desired for purposes of manufacturing detergents or for other end uses. It is found quite feasible, on the other hand, to manufacture triethyl aluminum, or ethyl aluminum compounds, having two or three ethyl groups in each radical, by the direct reaction of aluminum, ethylene and hydrogen, in the presence of a liquid reaction medium and reactant comprising triethyl aluminum, asis disclosed in US. Patent 2,787,626. Accordingly, although triethyl aluminum can be manufactured readily in a relatively high degree of purity, or at least with substantially no random distribution of alkyl chain lengths in the product, the similar situation has not been feasible with respect to the higher alkyl aluminum compound. Accordingly, a significant need has existed where by narrow-cut higher alkyl aluminum compounds can be produced, by this term meaning that alkyl compounds of aluminum can be produced wherein there is very little statistical distribution insofar as the chain length of the alkyl group is concerned. A related or similar need is for an efficient process for the production of other hydrocarbon compounds of aluminum in which the hydrocarbon substituents are aryl substituted alkyl groups or hydrocarbon radicals other than alkyl groups.

A principal object of the present invention is to provide, generally, a new and improved process whereby hydrocarbon compounds of aluminum can be produced with a high degree of specificity. More particularly, an object of the present invention is to provide a process whereby an ethyl aluminum compound, such as, for example, diethyl aluminum hydride, triethyl aluminum, or diethyl aluminum halide, can be converted in good yields to a desired hydrocarbon compound of aluminum. Even more particularly, an object of particular embodiments is to provide a catalyzed process whereby an alkyl aluminum compound is produced having a high proportion of a specific alkyl or substituted alkyl radical attached to the aluminum molecules therein. Another specific object is to provide a process whereby relatively pure compounds such as trioctyl aluminum, dioctyl ethyl aluminum, octyl diethyl aluminum, and trihexyl aluminum, dihexyl ethyl aluminum, and similar alkyl compounds of aluminum are produced wherein there is very little geometric distribution of the length of the higher alkyl radical. The process of the present invent-ion involves, in its broadest form, the treatment of an ethyl aluminum compound, at moderately elevated temperatures, and in the presence of certain catalysts, with a terminally unsaturated, or alkene-1, hydrocarbon having at least three carbon atoms, and being free of branching from the sec ond carbon atom of the molecule. Such olefinic hydrocarbon can be a straight or branched alkene compound, or can be substituted by aryl or other cyclic groups. The catalysts employed are certain metal materials, introduced as the oxides or various salts. The suitable metals include the group VIII metals such as nickel, cobalt, iron, palladium or platinum, and manganese, copper, and titanium. The catalyst is fed as a salt or an oxide of a member of this group of metals. In carrying out the process an ethyl aluminum compound, such as, for example, triethyl aluminum, is mixed with the alkene-l, and with an appropriate quantity of the catalyst. The mixture is then heated, usually at near atmospheric pressure, to or near the normal boiling point of the mixture, and reaction is thus carried out. The ethyl radicals of the ethyl aluminum compound are displaced, at least in part, by the alkene-1 reactant hydrocarbon, which forms a corresponding radical attached joined to the aluminum from the ethyl aluminum compound.

. It will be understood that the precise conditions of op eration will vary to a significant extent, dependent upon the precise olefinic hydrocarbon employed as a reagent, and to the proportions of materials charged, and also, to the effect of any inert hydrocarbon media employed if these are used. In most cases, it is found highly desirable to maintain a substantial excess of the olefinic reactant over the stoichiometric requirements. Inother words,

a 7 aaeams 7 determining the sto-ichiometric requirement on the basis of the aluminum material present, it is frequently desira-' ble to provide an excess of from 100 to 300 percent over the theoretical needs.

The details of the invention and of several preferred modes of operation will be readily understood from the detailed description and examples given below.

Example I Triethyl aluminum and octene-l were charged to a reaction flask in the proportions of 3 moles of octene to one mole of triethyl aluminum, or stoichiometric equivalents. In addition the reaction mixture contained about 53 volume percent toluene as a liquid reaction diluent. As a catalyst, nickel oxide, NiO, was added in the proportions of about 0.06 mole per mole of triethyl aluminum in the charge. The charge mixture was heated to refluxing temperature and was heated at this temperature and atmospheric pressure for approximately one hour. During this period, there was a steady evolution of ethylene gas, the total evolved corresponding to about 35 percent of the ethvl radicals in the triethyl aluminum originally charged. This showed that this proportion of ethyl groups had been replaced by octyl groups during the course of the reaction. This result was confirmed by hydrolysis treatment of the liquid reaction product after the reaction was terminated. By this method, the liquid reaction residue is treated with water, which results in the decomposition of the alkyl aluminum compounds therein and release of corresponding hydrocarbons. In this operation, ethane gas was given oif corresponding in volume to a large proportion of the ethyl groups on the original triethyl aluminum charged which had not been displaced by the octene-l.

Example II In this operation triethyl aluminum and octene-l were again used in stoichiometric proportions, of three moles of the octene to one mole of triethyl aluminum, and employing anhydrous nickel sulfate as a catalyst in the proportions of 0.01 mole per mole of triethyl aluminum. However, no hydrocarbon diluent was employed. Upon heating and refluxing the reaction mixture for approximately two hours, approximately 40 percent of the ethyl groups were displaced by octyl groups, resulting in evolution of a corresponding amount of ethylene gas. The identity of the product was demonstrated by hydrolysis of the liquid phase which resulted in release of additional light hydrocarbon-ethzine-corresponding to the ethyl groups not displaced by the octene, and showing that the product, before hydrolysis, was substantially diethyl octyl aluminum. In addition to this component of the product an appreciable proportion of dioctyl ethyl aluminum was present.

Example III The operation of the preceding example was repeated, except that instead of nickel sulfate, 0.02 mole of cobaltous chloride, CoCl per mole of triethylaluminum was employed as a catalyst. Comparable results were achieved, i.e. approximately /a of the ethyl groups of the triethyl aluminum were replaced by octyl groups.

It is found that an initial excess of the higher alkene reagent, in carrying out the reaction, is significantly helpful in providing a higher degree of displacement in formation of the desired long chain alkyl aluminum compounds. This is shown by the following example.

Example IV In this operation the same procedure as in Example III above was employed, except that the quantity of octene-l originally charged was doubled, providing 100 percent excess. The degree of reaction was increased to 62 percent displacement of the original ethyl groups by octyl groups.

,Further improvement is achieved by even higher excesses of the olefin hydrocarbon, as shown by the example below.

Example V The procedure of the preceding examples was repeated, except that the octene-l was used in the molar ratio of 9 moles per 1 mole of triethyl aluminum charged, or a 200 percent excess over stoichiometric requirements. The catalyst in this instance was nickel sulfate in the proportions of 0.036 mole per mole of triethyl aluminum. After a reaction period at reflux temperature for 1.5 hours, percent of the ethyl groups had been replaced by the octene.

In addition to the above described catalysts, good results had been achieved with additional catalysts comprising oxides or salts of other metals of the defined group of transition metals, as shown by the following group of operations:

Although the present invention finds most common use in the displacement of ethyl groups from ethyl aluminum compounds such as triethyl aluminum or diethyl aluminum hydride, it is also fully adaptable to the displacement of ethyl groups from ethyl aluminum chloride compounds as shown by the following example.

Example IX In this operation the ethyl aluminum compound was diethyl aluminum chloride, which was reacted with percent octene-l. Nickel sulfate was employed in the proportions of 0.05 mole per mole of diethyl aluminum chloride. On reacting for approximately 1 hour, about V2 of the ethyl groups of the diethyl aluminum chloride were replaced by octyl groups.

Example X In this operation triethyl aluminum and octene-l were reacted in stoichio-metric proportions of three moles of octene-l to one mole of triethyl aluminum. In addition, finely divided titanium dioxide was added in proportions of 0.054 mole per mole of triethyl aluminum. Upon heating at reflux conditions a steady reaction occurred with ethylene evolution. A conversion of 18 percent to octyl aluminum groups was obtained in 4 hours.

As previously stated a wide variety or number of alkene-l compounds can be employed as reactants, said reactants all having the terminal group H C=CH-, and having a content of three to about 18 carbon atoms. Although a high degree of branching of the reactant is entirely permissible, in all instances there should be no branching from the secondary carbon atom. In other words, alkyl or other hydrocarbon substitucnts in the molecule should not be positioned closer to the double bond than the third carbon. The applicability of the process with other aliphatic olefins or alkene-1 reactants is illustrated by Example XI below.

Example XI The procedures of Examples I-X, inclusive, are repeated, except that the following olefinic compounds are used instead of the octene-l: propylene, n-butene-l, npentene-l, 3,3-dimethyl pentene-l, 3,3-dimethyl butene-1, 4 methyl pentene l, 3.4-dmethyl nentene-l. 7-methvloctene-l, decene-l, nonene-l, dodecene-l, and branched derivatives of these alkene hydrocarbons, and other alpha olefins, derived from wax cracking, having up to 16 or 18 carbon atoms. Comparable results are readily achieved, the conditions of operation being adjusted in accordance with the properties of the olefins.

The presence of minor quantities of halogen substituents is quite permissible on the olefin reacted, thus, monochloro and other monohalo derivatives are quite suitable.

In addition to the straight or branched chain alkene hydrocarbons which can be employed as shown by the preceding examples, olefins having cyclic substituents are frequently employed. Thus, when 3-phenyl-propene-1, vinyl cyclohexane, or styrene are employed as the olefinic reactants, good results are customarily provided.

As illustrated by the preceding examples, the benefits of the invention are not confined to the employment of the triethyl aluminum compounds as feed reactants. Thus, as illustrated by Example IX above, an ethyl aluminum halide is quite satisfactory, and further, an ethyl aluminum hydride such as diethyl aluminum hydride is a similar equally suitable feed material.

The yields or conversion per pass or batch, in some cases, are too low for the best economics of operation. Overall materials efliciency can be then improved by higher catalyst concentrations, by recycle of the unreacted reactants or by longer contact times. Contact times of from one-half hour to about four hours per batch or per cycle are customarily employed.

A wide variety of catalysts can be employed and are suitable for the process. In addition to the catalysts specifically illustrated by the examples, numerous other salts of the metals can be employed with a high degree of success. Illustrative catalysts, then are nickel acetate, nickel chlorides, nickel carbonate, nickel iodide, ferric or ferrous bromide or chloride, iron hydroxide, cobaltic acetate, cobaltic or cobaltous chloride, cobalt oxides and cobalt sulfate, the oxides of manganese, manganese sulfates, copper acetates and sulfates, titanium chlorides and copper iodide. The valence state of the metal is not a significant factor in the efiicacy of catalyst compound thereof, both the higher and lower valence compounds being eifective. Similarly, catalysts which contain some water of hydration can be used, although this tends to react with the ethyl aluminum compound, thus reducing somewhat the materials efficiency of the process. Generally, it appears that the compounds employed as catalysts should be relatively refractory with respect to being reduced by the ethyl aluminum compound reactant. In other words, the metal proper is not, apparently, the sole effective catalyst component. Thus, when an attempt was made to carry out the reaction of octene-l With triethyl aluminum, using Raney nickel as a promoter or catalyst, virtually no reaction occurred.

The catalysts specifically illustrated above, viz.,, the oxides or salts of manganese, copper, titanium, iron, nickel and cobalt are an especially effective group of readily available and economic catalysts. However, comparable compounds, of other metals of group VIII of the periodic table in addition to iron, nickel, and cobalt, can be employed. Thus, when the oxides or salts of platinum, palladium, chromium, ruthenium, rhodium and iridium are employed as catalysts, similar good conversions, and displacement of the ethyl groups, will be achieved. Although oxides and halides are the preferred catalysts, salts of various other acids can be employed, such as acetates, nitrates, sulfates or phosphates.

With respect to the catalyst concentration employed, proportions of from 0.005 to as high as 0.1 mole per mole of triethyl aluminum, with corresponding revision when the ethyl aluminum compound contains less than three ethyl substituents per molecule. A preferred range of catalyst concentration is from 0.01 to 0.06 mole per mole of the aluminum ethyl reactant.

As clear from the preceding examples, the operating conditions of the process are relatively mild. Thus, in virtually all cases, the temperature can be the temperature at which refluxing occurs at atmospheric pressure or pressures of only a few pounds. Thus, the actual temperatures of operation will vary to a great extent dependent onthe constituents of the reaction mixture. In the case of the use of propylene or butene, it is frequently found desirable to employ a substantially inert, high-boiling aromatic hydrocarbon as an inert diluent. Thus, toluene, xylene, or similar aromatics can be provided, usually in proportions of about 40 to 60 volume percent of the reaction 'mixture. Alternatively, when the alkene reagent is quite volatile, as in these instances, application of modest pressures, to achieve temperatures of the order of 50 to 200 C., are frequently desirable. On the other hand, when employing olefinic reactants of greater molecular weight, or larger chain length in the case of the normal alkenes, or above 6 carbon atoms, it is usually found that a high boiling reaction medium or diluent is not required.

As clear from the examples given above, a susbtantial excess of the olefin reagent is desirable when a high degree of displacement of the ethyl groups on the ethyl aluminum feed is desired. Thus, the preferred reaction ratio in the reaction zone is from at least one to about 5 moles of olefin reagent per ethyl group or radical on the ethyl aluminum feed material.

When the reaction conditions and times and the relative proportions of the olefin reagent are such that only partial displacement and substitution of ethyl groups is achieved, the product will frequently have a variable composition including from one to three newly substituted alkyl groups. Thus,'for example, when reacting triethyl aluminum with heptene-1, and employing feed ratios corresponding to stoichiometric requirements, the product mixture will include minor amounts of triheptyl aluminum, and some triethyl aluminum which has not reacted. In addition, the reacted mixture will include roughly equal proportions of diheptyl ethyl aluminum and heptyl diethyl aluminum. The feed mixture thus obtained can be separated into the individual components by known physical means of separation, preferably at low pressures, or, alternatively, can be employed as such in subsequent processing steps.

The precise techniques of operation will vary to considerable extent, being determined for any particular embodiment by the characteristics of the reactants and the equipment available. In practically all cases, the best results are obtained by continuously venting the ethylene gas released, accompanied by refluxing any vaporized liquid concurrently vaporized from the reaction mixture.

From the foregoing description, and examples, it is clear that the present invention is susceptible to numerous variations without sacrificing the benefits thereof and is limited only by the claims below.

We claim:

1. A process for the manufacture of hydrocarbon aluminum compounds comprising forming a reaction mixture from an ethyl aluminum compound, an alkene-l hydrocarbon having at least three carbon atoms and the terminal group H C=CH, and a catalyst selected from the group consisting of the salts and oxides of a metal of group VIII of the periodic table and manganese, titanium and copper, said catalyst being provided in the proportions of from about 0.005 to 0.1 mole per mole of the ethyl aluminum compound, and heating said reaction mixture at a temperature of from about 50 to 200 C. sufficiently to displace ethylene from the ethyl aluminum compound and substitute therefor an alkyl radical corresponding to the alkene-1 hydrocarbon.

2. The process of claim 1 further defined in that the ethyl aluminum compound is triethyl aluminum.

3. The process of claim 1 further defined in that the ethyl aluminum compound is diethyl aluminum chloride.

4. The process of claim 1 further defined in that the catalyst is a nickel sulfate.

5. The process of claim 1 further defined in that the catalyst is a chloride of cobalt.

6. Theproeess of claim 1 further defined in that the catalyst is a chloride of manganese.

. catalyst is an oxide of nickel.

9'. The process of claim 1 further defined in that the catalyst is an oxide of titanium.

- References. Cited in the file of this patent UNITED STATESv PATENTS Ziegler et a1 May 20, 1958 Johnson Dec. 9, 1958 OTHER REFERENCES Chemical Abstracts, vol. 50 (1956), col. 9056f. Chemical Abstracts, vol. 51 (1957'), col- 15,993b. 

1. A PROCESS FOR THE MANUFACTURE OF HYDROCARBON ALUMINUM COMPOUNDS COMPRISING FROMING A REACTION MIXTURE FROM AN ETHYL ALUMINUM COMPOUND, AN ALKENE-1 HYDROCARBON HAVING AT LEAST THREE CARBON ATOMS AND THE TERMINAL GROUP H2C=CH-, AND A CATALYST SELECTED FROM THE GROUP CONSISTING OF THE SALTS AND OXIDES OF A METAL OF GROUP VIII OF THE PERIODIC TABLE AND MANGANESE, TITANIUM AND COPPER, SAID CATALYST BEING PROVIDED IN THE PROPORTIONS FOR FROM ABOUT 0.005 TO 0.1 MOLE PER MOLE OF THE ETHYL ALUMINUM COMPOUND, AND HEATING SAID REACTION MIXTURE AT A TEMPERATURE FO FROM ABOUT 50 TO 200*C. SUFFICIENTLY TO DISPLACE ETHYLENE FROM THE ETHYL ALUMINUM COMPOUND AND SUBSTITUTE THEREFOR AN ALKYL RADICAL CORRESPONDING TO THE ALKENE-1 HYDROCARBON. 